Enithares quadrispinosa Lansbury, 1967

Zettel, Herbert, Lane, David J. W., Pangantihon, Clister V., Freitag, Hendrik & Be, Jalan Tungku Link, 2012, Notes on Notonectidae (Hemiptera: Heteroptera) from southeastern Asia, mostly from Brunei and the Philippines, Acta Entomologica Musei Nationalis Pragae 52 (1), pp. 29-48 : 39-41

Enithares quadrispinosa Lansbury, 1967

( Figs. 11 , 15 )

Enithares freyi quadrispinosus Lansbury, 1967: 94 ; LANSBURY (1968: 436); CHEN et al. (2005: 422); YOUNG (2010: 47).

Enithares quadrispinosa: NIESER & ZETTEL (1999: 132) .

Material examined. PHILIPPINES: PALAWAN: El Nido, barangay Villa Libertad , 50 m a.s.l., 11°12′N 119°26′E, small creek, 15.x.1994, leg. H. Freitag (113bM), 1 J ( HFDG) ; Taytay, one-third of way to Lake Manguao, Manguao stream tributary, in primary forest, 35 m a.s.l., 10°47′N 119°31′E, 29.iv.1995, leg. H. Freitag (13bM), 1 J 1 ♀ ( NHMW) ; Taytay, Poblacion, southern Manguao stream tributary, 30 m a.s.l., 10°46′00″N 119°30′43″E, 14.ix.2007, leg. H. Freitag (63aM), 2 JJ 1 ♀ ( HFDG) ; Taytay, Poblacion, Manguao southwestern bay, Malibongbong Creek , 20 m a.s.l., 10°44′29″N 119°31′25″E, 7.v.2008, leg. H. Freitag (72aM/E), 2 JJ ( PCSD) ; Taytay, Manguao tributary east of Sinangalit Creek , 20 m a.s.l., 10°46′58″N 119°31′25″E, 3.xi.2008, leg. H. Freitag (73aM), 1 ♀ ( UPLB) ; Taytay, Lake Manguao, northeastern tributary, Pahok creek , 10°46′56″N 119°32′01″E 100 m a.s.l., residual pool, 7.v.2008, leg. H. Freitag (74aM), 1 J 1 ♀ ( PCSD) ; Taytay, barangay Abongan, Ibangley , Abongan River tributary, km 177.9 on Northern Highway , 10°37′23″N 119°23′17″E, 3.xi.2007, leg. H. Freitag (118M), 1 ♀ ( UPLB) ; Taytay, Poblacion, Manguao , temporary tributary at northern coast, Mechico Creek , 10°46′37″N 119°33′14″E, 20 m a.s.l., in degraded primary forest, 4.xi.2007 and 29.viii.2008, leg. H. Freitag (119)M, 1 J 3 ♀♀ ( NHMW) ; Taytay, Poblacion, Manguao , Malarad Creek , 20 m a.s.l., 10°46′22″N 119°33′36″E, 4.xi.2008, leg. H. Freitag (120M), 1 J 1 ♀ ( USCP) ; Taytay, Poblacion, Manguao , Enolbong Creek , 20 m a.s.l., 10°46′40″N 119°32′19″E, 5.xi.2008, leg. H. Freitag (121bM), 1J ( HFDG) ; Taytay, Poblacion, Manguao , Mecadlum Creek , 30 m a.s.l., 10°45′45″N 119°34′00″E, 29.viii.2008, leg. H. Freitag (146M), 1 J ( HFDG) ; Taytay, barangay Poblacion , 4 km southeast of town proper, 15 m a.s.l., 10°48′05″N 119°33′02″E, small hill stream, 21.viii.2007, leg. H. Freitag (100M), 1 J 2 ♀♀ ( ZRCS) ; Taytay, barangay Bato , mountain creek beside highway, 80 m a.s.l., 10°44′56″N 119°30′20″E, 22.viii.2007, leg. H. Freitag (101M), 1 ♀ ( HFDG) ; northern Palawan, Taytay, Poblacion, Malaipit Camp Site , Tuboc Creek , 30 m a.s.l., 19.xi.2007, leg. H. Zettel (490), 3 JJ 1 ♀ ( NHMW) ; northern Palawan, northeast of Roxas, Bagongbayan Falls , 40 m a.s.l., 17.xi.2007, leg. H. Zettel (488), 3 JJ 3 ♀♀ ( NHMW, ZRCS) ; Roxas, barangay Abaroan, Candelaria , Road to Port Barton , 10°20′14″N 119°16′29″E, small temporary creek, 16.xi.1995, leg. H. Freitag (127cM), 1 J ( HFDG) ; Roxas, Barangay 4, Umalad Falls , 3.5 km west of town proper, near water plant, 15 m a.s.l., 10°19′36″N 119°19′30″E, 24.iv.1995, leg. H. Freitag (69M), 1J 1 nymph ( HFDG) ; southwest of Roxas Poblacion, Umalad Falls , 50 m a.s.l., 16.xi.2007, leg. H. Zettel (485), 5 JJ ( NHMW, UPLB) ; Puerto Princesa, Concepcion, Taranaban River , 6 km upstream from Highway, 150 m a.s.l., 10°02′30″N 119°00′45″E, mountainous river, 20.i.1995, leg. H. Freitag (16bM), 1 J ( HFDG) ; Puerto Princesa, Concepcion, Taranaban River , 8 km upstream from Highway, 450 m a.s.l., 10°05′N 119°01′E, mountainous river, 28.i.1995 leg. H. Freitag (16fM), 1 ♀ ( HFDG) ; Puerto Princesa, Langogan, Highway km 79.9, 10°01′23″N 119°06′52″E, 20 m a.s.l., roadside pool under secondary vegetation, 21.viii.1994, leg. H. Freitag (142bM), 1 J ( HFDG) ; Puerto Princesa, Sabang, Mount Bloomfield Waterfall , 150 m a.s.l., 10°12′03″N 118°53′04″E, 8.x.2007, leg. H. Freitag (18M), 1 ♀ ( HFDG) ; Central Palawan, 9 km southsouthwest of Puerto Princesa, Luzviminda , 50 m a.s.l., 9°39′N 118°38′E, forest creek and falls, 14.xii.1994, leg. H. Freitag (17cM), 2 ♀♀ ( NHMW) ; Puerto Princesa, Santa Lourdes, km 15 of Northern Highway, stream at Magarwak Bridge , 28.xi.2007, leg. H. Zettel (499), 1 J ( NHMW) ; Puerto Princesa, Simpucan, Tagkuriring Falls , 120 m a.s.l., 9°47′26″N 118°33′25″E, 8.ix.1994, leg. H. Freitag (150bM), 2 JJ 1 ♀ ( HFDG) ; Napsan, km 43 of Napsan Road, Salakot Waterfalls , 310 m a.s.l., 30.xi.2007, leg. F. E. Bendanillo (4), 2JJ 1♀ ( USCP) ; Puerto Princesa, barangay Napsan, km 42.5 of Napsan Road, Salakot Falls , small tributary to Iwahig River , 9°42′05″N 118°31′18″E, 30.xi.2008, leg. Freitag (132aM), 1 J 1 ♀ ( HFDG) ; Espanola, barangay Abo-Abo, sitio Tumarbong , Liang River headwater, 1 km southwest of Highway , 9°10′N 118°03′E, 13.v.1995, leg. H. Freitag (76bM), 1 ♀ ( HFDG) ; Narra, 5 km west of town proper, Taritien River , 9°18′11″N 118°22′35″E, 100 m a.s.l., 17.iv.1994, leg. H. Freitag (182a), 1 ♀ ; Brookes Point, Salogon, Sitio Tagbinacao , 130 m a.s.l., 8°43′41″N 117°42′16″E, 24.iv.2010, leg. C. V. Pangantihon (147M), 2 ♀♀ ( NHMW) ; Brookes Point, Salogon, Sitio Tagbinacao , temporary tributary to Tagbinacao River , 130 m a.s.l., 8°43′41″N 117°42′16″E, 1.ix.1994, leg. H. Freitag (147cM), 1J ( HFDG) ; Brookes Point, Salogon, Sitio Tagbinacao , 8°43′44″N 117°42′32″E, 120 m a.s.l., small temporary creek, 1.ix.1994, leg. Freitag (149M), 1 ♀ ( HFDG). BALABAC: barangay Indalawan , Indalawan Falls , 7°54′44″N 117°02′40″E, pool, 23.v.1994, leg. H. Freitag (85M), 1 J ( NHMW) .

Notes. The taxon was originally described as a subspecies of E. freyi , but raised to species rank by NIESER & ZETTEL (1999). Erroneously, it was listed again as a subspecies by CHEN et al. (2005) and YOUNG (2010). Enithares freyi and E. quadrispinosa differ in a good number of characters including body size, colour and genitalia of males. In their key, NIESER & ZETTEL (1999) give a body length of 11.4–11.7 mm for E. freyi and ‘up to 10.6 mm’ for a set of species including E. quadrispinosa . Measuring more specimens, the range of body lengths is 11.3–12.7 mm (n = 27) in E. freyi , and 8.6–9.9 mm (n = 45) in E. quadrispinosa . The body shape is slightly more elongated but less acuminated in E. freyi than in E. quadrispinosa (comp. Figs. 9 and 11 ). Both species show wide variations in body colour. In E. freyi dark forms are dominant; the mesoscutellum is mostly black ( Fig. 9 ), and we have seen only a single specimen with yellow spot covering an area slightly exceeding 50 % of the entire visible surface. In contrast, most specimens of E. quadrispinosa are pale, the yellow area covering 75 to (usually) 100 % of the mesoscutellum ( Fig. 11 ). Chaetotaxy of the first mesotarsomere of the male differs considerably: Whereas E. freyi possesses four setae in a row, as in the female, E. quadrispinosa has two pairs of short, stout setae at the segment’s basal half. The distal part of the paramere is slender-triangular in E. freyi and narrow-digitiform in E. quadrispinosa ( NIESER & ZETTEL 1999) . However, the most distinctive character in males is the very different shape of the lateral arms of the basal plate (comp. Figs. 14 and 15 ). From an ecological viewpoint, both species inhabit similar microhabitats, i.e. pools and quiet bays in streams, but E. freyi is a mountain species (ca. 600–1200 m a.s.l.) and E. quadrispinosa occurs in lowlands (ca. 20–150 m a.s.l.).

From LANSBURY’ s (1968) description of the pale type specimens, YOUNG (2010) concluded that he described the flightless morph, and the ‘normal morph’ is unknown. However, the situation is more complicated. As a preliminary study, we have dissected 37 specimens with varying colour pattern and only 6 pale specimen of both sexes had reduced indirect flight muscles. Among the 31 specimens with well-developed flight muscles, some are completely pale, too. All examined specimens had completely developed hind wings. Despite the small number of examined specimens, the high frequency of individuals with flight abilities corresponds well with the rather unstable conditions of the species’ microhabitats.

Distribution. Enithares quadrispinosa , endemic to the Palawan region, is widespread and common on Palawan Island, and recorded from Balabac Island for the first time.

Figures

Figs. 8–13. Notonectinae. Habitus, dorsal aspect: 8 – Aphelonecta philippina Zettel, 1995, male. 9 – Enithares freyi Brooks, 1948, male. 10 – E. intha Paiva, 1918, female. 11 – E. quadrispinosa Lansbury, 1967, male. 12 – E. sinica (Stål, 1854), male. 13 – E. subparallela Lansbury, 1968, male. © NHMW Hemiptera Image Collection.

Fig. 14–19. Enithares Spinola, 1837, morphological details. 14–15 – lateral arms of basal plate of aedeagus, left aspect: 14 – E. freyi Brooks, 1948; 15 – E. quadrispinosa Lansbury, 1967. 16–17 – left mesotrochanter of female, ventral aspect: 16 – E. intha Paiva, 1918 (sp = spur); 17 – E. sinica (Stål, 1854). 18–19 – metaxiphus of female, ventral aspect: 18 – E. intha; 19 – E. sinica.